ipopolysaccarides (LPS), isolated from phase I and phase II oxiella burnetii, were analyzed. Purification of LPS by ltracentrifugation gave similar yields for both LPSI and IPSII. Purified PLSI and LPSII contained roughly 0.8 to 0.6% rotein. The fatty acid constituents of the LPSs were ifferent in composition and content, with branched chain fatty cids representing about 15% of the total. eta-hydroxymyristic acid was not detected in either LPSI or PSII. A thiobarbituric acid-periodate positive compound was vident in the LPSs, however, this compound was not identified s 3-deoxy-D-mannooctulosonic acid by gas and paper hromatography. LPSII contained D-mannose, D-glucose, -glyceromannoheptose, glucosamine, ethanolamine, -deoxy-mannooctulosonic acid-like material, phosphate, and atty acids. LPSI contained a unique disaccharide alactosaminuronyl-glucosamine and nine unidentified components n addition to the same components of LPSII. Analysis of LPSs y SDS-PAGE followed by silver staining indicated that LPSII as composed of only one band, while LPSI consisted of six or ore bands with irregular spacing. hromosomal DNA has been extracted from Nine Mile phase I oxiella burnetti. Chromosomal DNA has been cloned in a -based vector system of E. coli. A library of 150 plaques, epresenting about 1750 kilobases (kb), has resulted. The vidence suggests that rickettsial DNA is being expressed in at east some of these clones. A 36 kb plasmid Q phase I has been reviously described in C. burnetii. It has been successfully xtracted from several different strains (phase I and phase I). Restriction patterns so far appear almost identical, hough there may be some subtle differences. This plasmid from the Henzerling strain) has been cloned in the E. coli lasmid vector pBR322.